Gene Research Sheds Light on Rare Immune Disease

WEDNESDAY, Jan. 11 -- A genetic mutation that causes a rare immune disease characterized by impaired and excessive immune function has been identified by scientists.

Symptoms of the disorder include immune deficiency, inflammatory skin disorders and cold-induced hives (cold urticaria), according to the report published online in the Jan. 11 edition of the New England Journal of Medicine.

The U.S. National Institutes of Health team identified the genetic mutation in 27 members of three unrelated families who suffered from cold urticaria, a potentially serious allergic disease triggered by exposure to cold temperatures.

The mutation occurs in a gene for phospholipase C-gamma2 (PLCG2), an enzyme involved in the activation of immune cells, the investigators found.

The researchers have named the immune disorder PLCG2-associated antibody deficiency and immune dysregulation (PLAID).

"This is one of few examples in which the allergy symptom directed us to a genetic syndrome," study leader Dr. Joshua Milner, of the Laboratory of Allergic Diseases at the U.S. National Institute of Allergy and Infectious Diseases (NIAID), said in a news release from the institute.

"In trying to understand the link between this group of conditions -- autoimmunity, chronic infections and cold urticaria -- we not only identified a disease-causing mutation but uncovered a unique and fascinating genetic mechanism at the crux of allergy, immune defense and self-tolerance," Milner added.

"Investigating rare diseases gives researchers more clues about how the healthy immune system functions," NIAID director Dr. Anthony Fauci said in the news release. "More importantly, identifying the genetic cause of these disorders opens up possibilities for better disease management and potentially a cure for people who may have spent their entire lives debilitated by severe and unexplained symptoms."